Shop › DBB BBL 5.56NATO 16" MID MED 1/8 BLK DBB BBL 5.56NATO 16" MID MED 1/8 BLK $86.00 Diamondback Firearms Barrel, 223 Remington/556NATO, 16", 1:8 Twist, Black Nitride Finish, Mid Length Gas System, Threaded 1/2-28", Fits AR Rifles 556M16M50B8R Quantity: Add To Cart Added! Diamondback Firearms Barrel, 223 Remington/556NATO, 16", 1:8 Twist, Black Nitride Finish, Mid Length Gas System, Threaded 1/2-28", Fits AR Rifles 556M16M50B8R